To advance the understanding of how illicit markets operate and support violent anti-government groups, the United Nations Office on Drugs and Crime (UNODC) hosted a two-day expert's level technical seminar, Countering the Effects of Violent Transnational Crime, on 5-6 December 2007. The event, held at the Vienna International Centre (VIC), was sponsored by the U.S. Department of State and administered by the Institute for Defense Analyses (IDA). Attendance was by invitation only and was based upon technical expertise and experience. Seminar topics concentrated on histories of transnational crime and connections to anti-government/terrorist groups, similarities between criminal and terrorist network operations, the underlying organizational principles governing their behavior, and viable strategies for defeating them. The Colombian narco-insurgency and criminal activities in the surrounding regions were examined as the largest case study of successfully countering the legitimacy and capabilities of a criminal-based anti-government group. The consensus of the world-wide experts assembled at the seminar was as follows: (1) the failure to grasp and deal with emerging violent transnational criminal groups will continue to create larger and larger numbers of self-financed anti-government forces unless checked by efficient strategies, and (2) the emerging unfavorable situation in Afghanistan requires immediate application of the scientific principles enumerated in the seminar. This document presents the major findings of the technical seminar, a summary briefing of the seminar, and briefing charts for the 21 papers presented at the seminar.